Falling is a significant problem in the care of the elderly that can lead to morbidity and mortality. From a physical perspective, falls cause injuries, while from the mental perspective, falls cause fear-of-falling, which in turn leads to social isolation and depression.
Fall detection systems are being developed which can provide an automated and reliable means for detecting when a user has fallen. If a fall is detected, the system issues an alarm which summons help to the user. This assures the user that adequate measures will be taken in the event that a fall occurs.
Commonly, fall detectors are based on an accelerometer (usually a 3D accelerometer that measures acceleration in three dimensions) that is to be attached to the user's body. The fall detector processes the signals from the accelerometer to determine whether a fall has taken place. Unfortunately, however, as these fall detectors only include a single sensor, they often lack sensitivity and/or specificity.
Therefore, some fall detectors make use of further sensors, such as gyroscopes or air pressure sensors, to achieve high sensitivity and specificity.
However, each of these types of multiple sensor fall detectors have their own disadvantages. For example, gyroscopes provide highly reliable data, but they are unfeasible for a small body-worn portable device due to their size and energy consumption. Air pressure sensors can be used to provide altitude information (usually information on changes in altitude), but they only provide this altitude information at low sampling rates, making the reliable detection of falls challenging. Furthermore, it is difficult to mount air pressure sensors in fall detectors if the fall detector is to be water-resistant, which means that a special hydrophobic membrane and a dedicated pressure measurement chamber are required, as direct and sufficient air flow is required to the air pressure sensor.
Therefore, there is a need for an improved fall detector that overcomes the disadvantages with the conventional fall detectors described above.